The present invention relates to warning systems and, more specifically, vehicle back-up aid systems for collision avoidance.
Warning systems are being used today to alert vehicle operators of objects that may be a collision hazard when vehicles are backing up. Warning systems are also used as aids in precise parking maneuvers. Warning systems are desirable to minimize or avoid vehicle damage that may otherwise occur. Conventional warning systems are designed to give vehicle operators an audio or visual warning of an impending or potential collision with sufficient lead-time such that the vehicle operator can react to the warning and make appropriate countermeasures to prevent the collision.
Typically, such reverse sensing systems provide alerts to operators based on the relationship between the operator""s vehicle and a detected object. Conventional back-up aid systems, however, only alert the operator of a detected objected. The alert provided is not related to distance and the vehicle speed. The vehicle operator must, therefore, assess the seriousness of the alert without guidance from the back-up aid system. In other words, the alert does not inform the operator if the object is, for example, two feet away and rapidly approaching, or ten feet away and slowly approaching. Thus, conventional system alerts can be confusing, and operators may not process the alert quick enough to make appropriate countermeasures.
The present invention utilizes both distance to the nearest object and speed of the vehicle to determine time-to-collision (TTC) and give an appropriate warning based on this determined TTC. The warning system of the present invention communicates useful information to the driver by eliminating, for example, long range, low speed nuisance alarms. The present invention provides a hierarchical warning structure by informing a vehicle operator of the existence of an imminent crash warning, defined as the potential for a TTC within approximately 2 seconds; or a cautionary danger, defined as a TTC between approximately 2 to 5 seconds. Visual or audio warnings, or both, are provided so that the operator can take appropriate countermeasures.
The present invention is accomplished by providing a detection system that sweeps a predetermined area for objects. A control module having a microprocessor interprets the vehicle back-up speed and the location of any objects as sensed by the sweeps to determine the imminency of a potential collision. Based upon the imminency of a collision, a visual or audio signal, or both, is provided to the vehicle operator. In this way, the vehicle operator will be able to determine an appropriate countermeasure to prevent the collision without the need to additionally process the imminency of the potential collision.